His normal run looks really weird. Not the super fast one by olu, but the regular run. I can't pinpoint what it is...maybe it's his legs moving too fast and his is not covering distance...like a treadmill or running in place...maybe it's his upper body making it weird also

On another note...it might add a sense of speed and give more visually if you add speeding cars on the road passing by during the battle

Maybe another attack is where Reverse Flash makes time clones or mirages of himself.

Regarding Parasite he should start with just melee attacks and when he damages someone he gets a power from them. Superman's Hear Vision, Flash's speed, Batman's acrobatics, Wonder Woman's flight, Aquaman's water control, and Cyborg's teleportation via Boom Tube.